Generally, steel sections of various shapes, including H-beam steels, I-beam steels, channel beams, angle steels, steel plates and steel square tubes, are subjected to be drilled, milled and/or tapped in three different axial directions just for fitting the same to be fixed or to be ready for accessory installation.
In Japanese Unexamined Patent Application Publication No. Hei 11-165210, a steel section processing machine is disclosed, which comprises: a machine; a first door-type stand, mounted on the machine; a Z-axis direction processing unit, mounted on the first door-type stand; a second door-type stand, mounted on the machine at a side of the first door-type stand; a pair of Y-axis direction processing units, mounted on the second door-type stand. In addition, there are a pair of guide rails arranged respectively at the two sides of the second door-type stand that are extending in the Z-axis direction for enabling the two Y-axis direction processing units to move up and down respectively on the corresponding guide rails in the Z-axis direction.
Nevertheless, despite the aforesaid processing machine is quite capable of achieving a desirable and predictable machining effect, such processing machine is disadvantageous by the heavy weight of its Y-axis direction processing units. That is, as the guiderails are connected to a front side of the second door-type stand and the pair of the Y-axis direction processing units are mounted respectively on the guide rails, the positioning of the Y-axis direction processing units in correspondence to the second door-type stand can easily be displaced after a period of time for causing offset errors to the operating Y-axis direction processing units, and therefore, certain calibration procedure must be performed regularly so as to ensure a satisfactory processing accuracy to be achieved.